The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 03, 1986
Filed:
Jan. 14, 1985
Irving R Abel, Lexington, MA (US);
Honeywell Inc., Minneapolis, MN (US);
Abstract
Apparatus for continuously determining the position of best focus of an objective lens and a system having a video output. The technique uses a transmissive plate of variable thickness located on one side of the field stop of the optical system associated with the video output. The plate covers the full vertical field of the system and covers on the order of 30 to 40 resolution elements in the horizontal direction. The plate is divided vertically into platelets of different thicknesses which are distributed in such a way as not only to cover the range of defocus of the system, but to discriminate against possible variations in scene content. The plate is placed outside the active area which will be displayed by the video; therefore the variations in thickness and in focus introduced by the plate are not displayed on the video, but are only used for the purpose of continuously determining the position of best focus. A spherical shell of zero power may be placed between the objective lens and the field stop in order to create a bias so that focal shifts introduced by the plate may be distributed about a nominal position, rather than all in a positive direction.